|
type |
Journal Article |
authors |
Ohisalo, J. J.; Andersson, S. M.; Pispa, J. P. |
title |
Partial purification and properties of frog liver tyrosine aminotransferase |
journal |
Biochem J |
Activity |
2.6.1.5 |
Family |
2.6.1.5.a |
ui |
77221542 |
year |
(1977) |
volume |
163 |
number |
3 |
pages |
411-7. |
| |
keywords |
Aminooxyacetic Acid/pharmacology |
abstract |
Hepatic tyrosine aminotransferase of the frog Rana temporaria was partially purified by (NH4)2SO4 fractionation and successive chromatography on DEAE-cellulose DE-52, Ultrogel AcA-34, DEAE-cellulose DE-52 again and, finally, hydroxyapatite. During the last step, the enzyme activity separated into two fractions; traces of a third fraction were also found. The major form was purified 6000-fold to a specific activity of 200 units/mg of protein; it was about 50% pure by electrophoretic criteria. It had mol.wt. about 85 000 as determined by gel filtration on a Sephadex G-100 column. It was not activated by added pyridoxal 5'-phosphate. The enzyme was, however, inactivated by the pyridoxal phosphate reactants canaline and amino-oxyacetate. The enzyme was specific for 2-oxoglutarate as the amino group acceptor. Homogentisate inhibited the enzyme and adrenaline was an activator; both effects were seen at low concentrations of the effectors. The relationship between initial rate and tyrosine or 2-oxoglutarate concentration was abnormal and complex. Form-2 enzyme had similar or identical molecular weight, cofactor requirements, oxo acid specificity and kinetics. |
last changed |
2019/05/13 09:56 |
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